A Wobble Disk Air Motor With One Moving Part

October 22, 2024 by 1 Comment

In general, the simpler a thing is, the better. That doesn’t appear to apply to engines, though, at least not how we’ve been building them. Pistons, cranks, valves, and seals, all operating in a synchronized mechanical ballet to extract useful work out of some fossilized plankton.

It doesn’t have to be that way, though, if the clever engineering behind this wobbling disk air engine is any indication. [Retsetman] built the engine as a proof-of-concept, and the design seems well suited to 3D printing. The driven element of the engine is a disk attached to the equator of a sphere — think of a model of Saturn — with a shaft running through its axis. The shaft is tilted from the vertical by 20° and attached to arms at the top and bottom, forming a Z shape. The whole assembly lives inside a block with intake and exhaust ports. In operation, compressed air enters the block and pushes down on the upper surface of the disk. This rotates the disc and shaft until the disc moves above the inlet port, at which point the compressed air pushes on the underside of the disc to continue rotation.

[Resetman] went through several iterations before getting everything to work. The main problems were getting proper seals between the disc and the block, and overcoming the friction of all-plastic construction. In addition to the FDM block he also had one printed from clear resin; as you can see in the video below, this gives a nice look at the engine’s innards in motion. We’d imagine a version made from aluminum or steel would work even better.

If [Resetman]’s style seems familiar, it’s with good reason. We’ve featured plenty of his clever mechanisms, like this pericyclic gearbox and his toothless magnetic gearboxes.

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For Desalination, Follow The Sun

October 22, 2024 by 4 Comments

It’s easy to use electricity — solar-generated or otherwise — to desalinate water. However, traditional systems require a steady source of power. Since solar panels don’t always produce electricity, these methods require some way to store or acquire power when the solar cells are in the dark or shaded. But MIT engineers have a fresh idea for solar-powered desalination plants: modify the workload to account for the amount of solar energy available.

This isn’t just a theory. They’ve tested community-sized prototypes in New Mexico for six months. The systems are made especially for desalinating brackish groundwater, which is accessible to more people than seawater. The goal is to bring potable water to areas where water supplies are challenging without requiring external power or batteries.

The process used is known as “flexible batch electrodialysis” and differs from the more common reverse osmosis method. Reverse osmosis, however, requires a steady power source as it uses pressure to pump water through a membrane. Electrodialysis is amenable to power fluctuations, and a model-based controller determines the optimal settings for the amount of energy available.

There are other ways to use the sun to remove salt from water. MIT has dabbled in that process, too, at a variety of different scales.

The 2024 Hackaday Supercon SAO Badge Reveal

October 22, 2024 by 4 Comments

We’ve been hinting at it for a few months now, running a series of articles on SAOs, then a Supercon Add-On Challenge. We even let on that the badge would have space for multiple SAOs this year, but would you believe six?

Way back in 2017ish, Hackaday’s own [Brian Benchoff] and the [AND!XOR] crew thought it would be funny and useful to create a “standard” for adding small custom PCB art-badges onto bigger conference badges. The idea was to keep it quick and dirty, uncomplicated and hacky, and the “Shitty” Add On was born. The badge community took to this like wildfire. While the community has moved on from the fecal humor, whether you call these little badgelets “SAOs”, “Simple Add-Ons”, or even “Supercon-8 Add Ons”, there’s something here for everyone. So if you’ve already got some SAOs in a drawer, bring them to this year’s Supercon and show them off!

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Pushing The Plasma Limits With A Custom Flyback Transformer

October 22, 2024 by 3 Comments

For serious high-voltage plasma, you need a serious transformer. [Jay Bowles] from Plasma Channel is taking his projects to the next level, so he built a beefy 6000:1 flyback transformer.

[Jay] first built a driving circuit for his dream transformer, starting with a simple 555 circuit and three MOSFETs in parallel to handle 90 A of current. This led to an unexpected lesson on the necessity for transistor matching as one of them let out the Magic Smoke. On his second attempt, the 555 was swapped for an adjustable pulse generator module with a display, and a single 40 A MOSFET on the output.

The transformer is built around a large 98×130 mm ferrite core, with eleven turns on the primary side. All the hard work is on the secondary side, where [Jay] designed a former to accommodate three winding sections in series. With the help of the [3D Printing Nerd], he printed PLA and resin versions but settled on the resin since it likely provided better isolation.

[Jay] spent six hours of quality time with a drill, winding 4000 feet (~1200 m) of enameled wire. On the initial test of the transformer, he got inch-long arcs on just 6 V and 15 W of input power. Before pushing the transformer to its full potential, he potted the secondary side in epoxy to reduce the chances of shorts between the windings.

Unfortunately, the vacuum chamber hadn’t removed enough of the air during potting, which caused a complete short of the middle winding as the input started pushing 11 V. This turned the transformer into a beautiful copper and epoxy paperweight, forcing [Jay] to start again from scratch.

On the following attempt [Jay] took his time during the potting process, and added sharp adjustable electrodes to act as voltage limiters on the output. The result is beautiful 2.25-inch plasma arcs on only 11 V and 100 W input power. This also meant he could power it with a single 580 mAh 3S LiPo for power.

[Jay] plans to use his new transformer to test materials he intends to use in future plasma ball, ion thruster, and rail gun projects. We’ll be keeping an eye out for those!

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In Its Second Year, JawnCon Was Bigger And Better

October 22, 2024 by 6 Comments

Starting a hacker con is hardly what anyone would describe as easy — but arguably, the truly difficult part is keeping the momentum going into the second year and beyond. For the first year, you can get away with a few missed opportunities and glitches, but by the time you’ve got one event under your belt, you’ll have set the bar for what comes next. There’s pressure to grow, to make each year bigger and better than before. All the while, making sure you don’t go broke in the process. Putting on a single hacker con is an achievement in and of itself, but establishing a long-running hacker con is a feat that relatively few groups have managed to pull off.

With this in mind, the incredible success of the second annual JawnCon is all the more impressive. The Philadelphia-area event not only met the expectations of a sophomore effort, but exceeded them in pretty much every quantifiable way. From doubling attendance to providing a unique and immersive experience with their electronic badge, the team seized every opportunity to build upon the already strong foundation laid last year. If this was the make-or-break moment for the Northeast’s newest hacker con, the future looks very bright indeed.

But before setting our sights on next year, let’s take a look at some of the highlights from JawnCon 0x1. While you can watch all of this year’s talks on YouTube, the aspect of a hacker on that can’t easily be recorded is the quality time spent with like-minded individuals. Unfortunately, there’s no way to encompass everything that happened during a two-day con into a single article. Instead, this following will cover a few of the things that stood out to me personally.

If you’d like to experience the rest of JawnCon, you’ll just have to make the trip out to Philly for 2025.

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Libre Space Foundation Aims To Improve Satellite Tech

October 22, 2024 by 8 Comments

There’s no shortage of movies, TV shows, and books that show a dystopian future with corporations run amok in outer space with little or no effective oversight. Dune, The Expanse, and The Dispossessed spring to mind as predicting different aspects of this idea, but there are plenty of other warnings throughout sci-fi depicting this potential future. One possible way of preventing this outcome is by ensuring that space is as open-sourced as possible and one group, the Libre Space Foundation (LSF), is working towards this end. Their latest is a project with Ondsel to develop and model a satellite deploying mechanism using almost entirely open source software.

The LSF had already designed the PICOBUS satellite launcher system that flew to space in 2022 and deployed a number of CubeSats, but the group needed more information about how the system would perform. They turned to Ondsel to help develop a multi-body dynamics (MBD) solver, managing simulations with mass-spring-damper models. The satellite launcher includes a large constant-force spring that pushes the CubeSats out of the device once the door is opened, and the model can now simulate their paths in space without gravity. The team will launch their next set of satellites sometime next year on an RFA-ONE rocket.

The LSF maintains a huge database of their open source space projects, including this one, on their GitLab page. Although it might seem like small potatoes now, the adoption of open source software and hardware by space-fairing entities can help further the democratization of low Earth orbit.

Thanks to [johnad] for the tip!

“Click To Cancel” Coming Soon

October 22, 2024 by 22 Comments

If you’ve ever had to suffer through a call tree and a 9,000 hour wait on hold to cancel a subscription, we have good news for you if you live in the United States. The Federal Trade Commission (FTC) has just finalized a rule that will “make it as easy for consumers to cancel their enrollment as it was to sign up.”

The announcement of the proposed rule came in March 2023 and was followed up by 16,000 comments from the public. Complaints to the agency about negative option and recurring subscription services have been rising from 42 per day in 2021 to 70 per day in 2024.

Commission Chair Lina M. Khan says, “The FTC’s rule will end these tricks and traps, saving Americans time and money. Nobody should be stuck paying for a service they no longer want.”

The rule will take effect 180 days after entering the Federal Register. If you’re curious about other ways we can hold tech companies accountable, Cory Doctorow has some ideas.